Hello community,
I am trying to adjust my daily sales forecast so that the monthly calendar total matches the monthly "weekly-calendar" total, while keeping my seasonality as close to reality as possible.
A simple picture will tell more than 100 words.

.Spreadsheet here: https://docs.google.com/spreadsheets/d/1rL4AnoCCTUAX9zXmF0tW6wRhvYhddUdm_buRgf_5G9s/edit?usp=sharing
I am trying to get the green column 'resultNetSales'.
In order to do that, I need the orange column 'sum of daily sales over calendar month' to compute the sum of all netSalesEuroByDay that have the same calendarMonth as the current day.
In Excel, I would simply use the " =SUMIF($F$6:$F,F8,$D$6:$D) " formula.
I would have expected the formula " netSalesEuroByDay[SUM: calendarMonth ] " to give me that result, but it keeps throwing a horrible error:

Any idea on what formula to put in my orange column?
Or another way of achieving the result column differently?
Thanks a lot,
FX